1. Field of the Invention
This invention relates to a picture-taking system, as well as a picture taking method, equipped with a film camera for capturing the photographic image of a subject on a photosensitive film, and a video camera, which includes a solid-state electronic image sensing device, for outputting a video signal that represents the photographic image of the subject, wherein substantially identical optical images of the subject are captured by both the film camera and the video camera under a single flash of a strobe generated by a strobe light-emitting device.
2. Description of the Background Art
Picture-taking systems of this kind are used with great effectiveness in photographic halls and studios in order to verify whether the desired video has been obtained before developing or printing a film on which an image has been captured by a film camera. This is achieved by reproducing the video signal obtained from the video camera on a monitor display such as a television so that the picture may be displayed in advance of development or printing. What is of prime importance in such a picture-taking system is that essentially the same photographic image be obtained in both the film camera and video camera. If this is not accomplished, the reproduced image based upon the output video signal of the video camera will be of no help whatsoever.
In order to obtain essentially the same photographic image in both the film and video cameras, it is required that both cameras perform exposure simultaneously. In the photography of portraits or the like indoors such as in a photographic studio, a strobe is fired for exposure. Since exposure in the cameras is essentially governed by the time at which the strobe is fired, simultaneous exposure in these two types of cameras is possible if use is made of strobe illumination.
An important problem to be referred to is that a video camera operates in accordance with a synchronizing signal of a fixed period (e.g., a vertical synchronizing signal). In accordance with the NTSC (National Television System Committee) method, one period of a vertical synchronizing signal is 1/60 of a second (about 16.7 ms), and one field of a video signal is produced within this period. Accordingly, the operating period of the video camera must conform to strobe firing timing.
The principal camera employed in the above-described picture-taking system is a film camera. The purpose of the system is to acquire a film photograph that is satisfactory, and the video camera is nothing more than a means of confirming whether the film photograph is suitable or not.
For this reason, the idea that has prevailed heretofore is that it is important that the strobe be fired and the picture taken by the film camera in accordance with the timing at which a shutter-release button on the film camera is pressed. According to the conventional picture-taking system or method, the generally accepted technical concept is to set (synchronize) the operation of the video camera to the picture-taking timing of the film camera.
For example, according to U.S. Pat. No. 4,805,037, a strobe is fired immediately in response to operation of the shutter button on the film camera, thereby capturing the image of the subject by the film camera. A synchronizing device is provided for synchronizing the operation of the video camera to that of the film camera in such a manner that the video camera will take a picture identical with that taken by the film camera.
A system and method representing an improvement on the system of the above-mentioned literature are described in U.S. Pat. No. 5,006,871 and U.S. Pat. No. 5,008,697. In the former, the timing of the light emission of a strobe device is controlled by generating a flash fire signal based upon AND logic between the flash request signal output by the film camera and a flash valid signal output by the video camera. The latter is for preventing transfer of signal charge (the video signal) out of a solid-state electronic image sensing device for the duration of strobe illumination. In order to accomplish this, a synchronizing circuit is provided to interrupt the readout of signal charge from the solid-state electronic image sensing device in response to the flash request signal from the film camera and reset a synchronizing signal generating circuit following the conclusion of flash illumination to start the transfer of signal charge.
In either case, to the extent that these systems are based upon an approach that causes operation in the video camera to follow up and become synchronized to the picture-taking operation in the film camera and strobe illumination under the control of the film camera, the need for measures to set the operation of the video camera to the operation of the film camera, as well as some circuit means or other for achieving this, is unavoidable.